Problem with receiving texts over Wi-Fi

This is on two different phones, both on ATT, both running Nougat. One is a Samsung Galaxy S6 Active, the other is a Samsung Galaxy S7.

The issue is this: If someone sends a text message to either phone when it is not connected to the cell signal or a wi-fi signal, the texts are not delivered if the phone is connected to wi-fi only later. The text only comes through when connected to a cell signal.

This is a problem as one of the phones is used in a location with no cell signal, but does have access to wi-fi from time to time (and the other scenario is traveling in Canada with no international service, but wi-fi works). The receiver has no idea a text has been sent until they reconnect to cell service.

This is using the stock samsung app on both phones. It works fine if it is connected to wi-fi when the text is sent, but otherwise it won't receive it until the next cell connection. Both phones have Wi-Fi calling enabled (and it works great when connected).

There are times when I have that same exact problem. I think that text over Wi-Fi is simply not a perfected system yet. I have searched high and wide on the Internet tried all the recommendations but it still persists sometimes.

My solution has been to use WhatsApp. Unfortunately not everyone has WhatsApp so still stuck with not getting text messages sometimes.

I realize that hearing it just doesn't work sometimes doesn't seem like a great answer, however, I think that's the answer.

if you find something that permanently fixes the problem please post it here.

BTW, I am also on AT&T. I'm using Galaxy S7. I have found it doesn't matter if the text messages are coming from AT&T or from another service provider sometimes it just doesn't work.

I can tell you text messages don't require a cell signal if wi-fi calling is enabled on the phone. It works just fine when the phone is connected to wi-fi only.

The issue is when the phone is not connected (cell or wi-fi), and a wi-fi connection only is established. Any texts that were sent and waiting to be delivered aren't delivered until a cell connection is established. This is a problem when I am in Canada with no cell service but do have wi-fi, among other situations. Connecting to a cell signal is not an option (Does not exist in that area!).

I plan to try some other apps - luckily its easy to recreate the issue using our home wi-fi signal...

And we've found the same thing - it doesn't matter if the text is from an ATT user or other network (or an Iphone for that matter).